1. Field of the Invention
The invention relates to a touch pad for controlling the movement of a cursor on a visual display, more particularly to a touch pad module mountable on a notebook computer.
2. Description of the Related Art
For miniaturization of computer products, touch pads that perform the same function as a mouse device, have been developed to control the movement of a cursor in a visual display. As touch pads have a reduced size, they are advantageously used in notebook computers by mounting on a keyboard panel. As shown in FIGS. 1 and 2, a typical cursor control device comprises a touch pad body 1, a touch control region 2 with a sensing film 2a formed on a front side of the touch pad body 1, a control circuit 2b provided on a back side of the touch pad body 1, and a contact switch unit 3 electrically connected to the control circuit 2b by means of a flexible printed circuit member 4, such as a ribbon cable. The contact switch unit 3 is provided with a push button 3a and a movable contact unit 3b. Such a control device is not a unitary construction and thus tends to encounter problems in governing inventory. In addition, the manufacturing cost of such a control device is high due to the use of expensive ribbon cables. Moreover, the push button 3a raised from the touch pad body 1 occupies a certain height and is not advantageous for miniaturization.
Another conventional cursor control device is shown in FIGS. 3 and 4, wherein a contact switch unit 3xe2x80x2 is directly mounted on a touch pad body 1xe2x80x2 which has a touch control region 2xe2x80x2 covered by a sensing film 2axe2x80x2 and a control circuit unit 2bxe2x80x2. The contact switch 3xe2x80x2 has a push button 3axe2x80x2, a movable contact unit 3bxe2x80x2 loaded with a spring 3cxe2x80x2, and a stationary contact member 3dxe2x80x2 disposed on the touch pad body 1xe2x80x2. The stationary contact member 3dxe2x80x2 is electrically connected to the control circuit unit 2b via printed circuit lines. This type of control device has a unitary construction and dispenses with the use of the ribbon cables. However, since it still utilizes the push button 3axe2x80x2, the size thereof cannot be reduced satisfactorily. In addition, as the contact switch unit 3xe2x80x2 and the control circuit unit 2bxe2x80x2 are provided respectively at the front and back sides of the touch pad body 1xe2x80x2, soldering has to be carried out in two successive steps at two sides of the touch pad body 1xe2x80x2 and therefore is thus laborious.
The main object of the present invention is to provide a unitary touch pad module which can overcome the above-mentioned disadvantages.
According to the present invention, a touch pad module for controlling the movement of a cursor comprises: a plate; two resilient arms coplanar with the plate, each of the resilient arms having one end formed integrally with the plate and a free end part opposite to the one end, each of the resilient arms being bendable to permit the free end part to resiliently move away from the plane of the plate; a touch control region formed at a front side of the plate; a control circuit unit disposed opposite to the touch control region at a rear side of the plate; and a switching unit provided on a rear side of each of the resilient arms and electrically connected to the control circuit unit, the switching unit having a movable contact member projecting resiliently from the rear side of the corresponding one of the resilient arms.